Blood lead as a cardiovascular risk factor.

Many epidemiologic and experimental animal studies support the hypothesis of there being a causal association between lead exposure and increased blood pressure/cardiovascular disease. This study includes 1,052 men and women from Copenhagen County, Denmark, who were examined in 1976 and 1981; in 1987, only the men were examined. Blood lead fell by approximately 40% for the men during the 11-year period and by approximately 30% for the women during the first 5-year period. There was a univariate association between systolic blood pressure and blood lead for both sexes in 1976, but it disappeared at the following examinations. For women, there was also a significant association with diastolic blood pressure, even after confounders were controlled for at the two examinations. Moreover, the authors found a significant univariate association between changes in blood lead and changes in systolic blood pressure from 1976 to 1987 in the males. All participants taking part in the study in 1976 were followed regarding hospital admissions and deaths throughout a follow-up period lasting for 14 years. There was a significant univariate association with total mortality, coronary heart disease, and cardiovascular disease. However, with regard to coronary heart disease and cardiovascular disease, the associations disappeared when confounders were controlled for. Blood lead was a significant predictor of total mortality after control for relevant confounders. This study supports the hypothesis of there being a weak causal association between blood lead and blood pressure, total mortality, coronary heart disease, and cardiovascular disease. The importance of this association is very modest for the individual, but the population attributable risk may be considerable.